Cov yam ntxwv sib npaug
Lub xeev kev sib luag muaj cov yam ntxwv nram qab no
(1) Kev sib sau ua ke (P, T yog muaj sib npaug nyob txhua qhov chaw);
(2) kev ruaj khov ntawm lub xeev-ywj pheej ntawm lub sijhawm;
(3) qhov kawg ntawm cov txheej txheem tshwm sim;
(4) Thermal tshuav.